iOS itouch replaceObjectAtIndex navigation bar disappears - ios

Question

I have a family of devices that are very similar and are controlled by an applet with three tabs. Within each view controller, I make use of the navigation controller to expand into the set up of each one of those features.
The first tab, the 'input' tab, especially is quite different between these three devices so when it is detected that I've switched between devices, I perform the following thing in my application delegate:
if ([self IsCrescendo])
{
//thirdViewController is really the crescendo'a input view - I need to rename that mess one day
crescendoInputView = [[ThirdViewController alloc] init : (UIViewController*) currentViewController];
crescendoInputView.title = [[viewControllers objectAtIndex:INPUT_TAB_INDEX] title];
crescendoInputView.tabBarItem = [[viewControllers objectAtIndex:INPUT_TAB_INDEX] tabBarItem];
[viewControllers replaceObjectAtIndex:INPUT_TAB_INDEX withObject:crescendoInputView];
[crescendoInputView release];
[self.tabBarController setViewControllers:viewControllers animated:FALSE];
}
if ([self IsSpirito3])
{ // similar to above using obviously a different view controller
}
if ([self IsSonata])
{ // similar to above using obviously a different view controller
}
Initially, this app just controlled one device so when I first created it, I set the three tabs up in the main window's XIB which works well. It defaults to the original device and the navigation bar is in tact and working.
Now that there are more devices to control, I figured to just use a replaceObjectAtIndex so swap a new view controller in but my Navigation bar disappears.
I'd very much appreciate any light you may be able to shed on this.
Thanks!

Answer 1

Okay, after lots more head scratching, the following fixed it:
I had initially used the main window's XIB to instantiate the three tabs.
This works fine if you're not doing a replaceObjectAtIndex. When I did do a ReplaceObjectAtIndex, it would lose the navigation bar.
Instead, if you instantiate the tabs programmatically, along with each having its own navigation controller, you can replace tabs with impunity and not lose features like the navigation bar.
(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
// Override point for customization after application launch.
// Input view (defaults to Crescendo)
UIViewController *viewController1 = [[[ThirdViewController alloc] initWithNibName:#"ThirdView" bundle:nil] autorelease];
UINavigationController *nav1 = [[UINavigationController alloc] initWithRootViewController:viewController1];
// Volume View
UIViewController *viewController2 = [[[SecondViewController alloc] initWithNibName:#"SecondView" bundle:nil] autorelease];
UINavigationController *nav2 = [[UINavigationController alloc] initWithRootViewController:viewController2];
// System view
UIViewController *viewController3 = [[[FirstViewController alloc] initWithNibName:#"FirstView" bundle:nil] autorelease];
UINavigationController *nav3 = [[UINavigationController alloc] initWithRootViewController:viewController3];
self.tabBarController = [[[UITabBarController alloc] init] autorelease];
self.tabBarController.viewControllers = [NSArray arrayWithObjects:nav1, nav2, nav3, nil];
.
.
}
Not sure why it does not work when you set it up from a XIB. I could swear I had it working on a previous version so maybe something changed and apple forgot to tell us about it.
I like this approach better anyway. It isn't the first time a 'wizard like' programming tool has bit me so maybe this will save someone out there a little time.